Gelatino-silver halide photographic elements containing higher fatty alcohols



N 1943- w. H. DIMSDALE EIAL 2,454,043

GELATINO-SILVER HALIDE PHOTOGRAPHIC ELEMENTS CONTAINING HIGHER FATTY ALCOHOLS Filed March 24, 1945 FIG].

FILM BASE F/GZ/ I CELA TIN CON TAININC 0.5 M10 OF'SATURA TED ALIPI-IATIC GELATIN SILVER HALiDE EMULSION FILM BASE INVENTORS' WILFRID HAMPDEN DIMSDALE n; KENNETH JOHN CHAL us A T'TORNE Y PRIMARYMONOHYDRIC ALCOHOL OF ATLEASTIZ CARBONATOIIS Patented Nov. 16, 1948 GEILATINO S-IIJVER HALIDE PHOTOGRAPHIC {ELEMENTS CONTAINING HIGHER FATTY ALGQHOLS "Wilfrid Harnpden Dimsdale and Kenneth dohn -@hallis, Ilford, England, assignors to Ilford Limited; IlfordJEn'gland, a British company ApplicationMarch24, 1945, Serial No. 584,724 In Great Britain April 4, 1944.

7 Qlaims.

This invention relates to photographic materials and particularly to the production of photographic emulsions and photographic elements consisting ofa support carrying a layer of photographic emulsion.

"Photographic emulsions usually consist of a dispersion of one or-more silverhalides, e. g. silver bromide or silver chloride, in gelatin, though other colloidal binding agents have been proposed. It is found that suchemulsions, coated to form photographic elements, have a tendency to become soratchedinuse, and various methods of overcoming this difficulty have been proposed. Thus, in the case of film to be used for cinematographic purposes ithas been proposed to apply a coating of wax over the surface of the emulsion, this serving-apparently'as a lubricant and for that reason reducing the formation of scratch marks.

It has now been discovered-that the tendency for photographic emulsion layers and other outer colloid layers of photographic elements to become scratched in use maybe reduced'by including in the emulsion'layer or other outer colloid layer during its manufacture, or by'applying to the surface of the coated emulsion layer-or other outercolloiddayer; a small proportion of a higher fatty alcohol which is solid atordinary (room) temperatures.

The invention is of particular value in connectionwith the production of photographic materials carrying gelatino silver halide emulsions.

In the series of fattyalcohols, those containing 12 or more carbon atoms are solid at ordinary: temperatures, and the -present invention, I17

'thereforaenvisages the use of dodecyl' alcohol and the higher homologous members of the series, e. g; cetyl-alcohol, ceryl alcohol, miricyl'alcohol andstearyl alcohol. It is particularly to be observed that the compounds used are the free alcohols and not the corresponding esters.

One convenient method of adding the higher fatty alcohols to a photographic emulsion" is to dissolve the higher fatty alcoholin a solvent, e. g.

a lower fatty alcohol such as ethyl alcohol, and

stir the-resulting solution into the liquidphotographic emulsion'or' intothe colloid (or part thereof) which is to be used in making the photographic emulsion. Alternatively, the higher fatty alcohol may be added in molten form, i. e. at a temperature above its melting point. In general it is found desirable to include a small proportion of a dispersing agent in the photographic emulsion, or in the solution of the higher fatty alcohol, in order to facilitate dispersion of 2 the alcohol in the emulsion. Any of the well known surface-activewetting agents maybe em ployed for this purpose, e. g. soluble salts of long chain-alkyl carboxylic acids, of long-chain-alkyl sulphonic acids, of sulphated higher fattyalcohols, of sulphated long-chain secondary alcohols, or of alkylatedaromatic sulphonic acids]: Such soluble salts may be salts formed fromalkali metals or-ammoniaor: amines, eh g; triethan'olamine and cyclohexylamine. The various com mercial products sold. as'dispersing agents for use in the dyeing and textile industries maybe so employed.

The preferred method of incorporating the higher fatty alcohol in a photographic emulsion is to form an aqueous dispersion of the alcohol by the assistance of a dispersing agent-and to add this aqueous dispersion to the liquid-photographic emulsion or to a portion of the'colloid, usually gelatin, to be used in forming the photographic emulsion.

As indicated above, the higher fatty alcohol may be applied as a surface coating to theemulsion instead of being directly'incorporated therein. Thus the higher fatty alcohol in the form of an aqueous dispersion, in the form of a solution in a suitable solvent such as a lower alcohol, or in molten form, may be applied directly to the surface of the coated emulsion. Alternatively, the higher fattyalcohol maybe dispersed in a colloid medium, e. g. gelatin, and theresulting colloid dispersion coated as alayer over the photographic emulsion.

Only a small proportion of higher fatty alcohol is necessary to obtain the desired effect. The optimum proportion appears to depend on'th'e particular higherfattyalcoholemployed and, where the higher fatty alcohol is dispersed in the emulsion or a superposed colloid layer, on the nature of such emulsion or colloid layer; In general it is found'that for gelatin emulsions and colloid layers, proportions varying from about 0.5% to 10%, or even'more, on the weight of the gelatin or other colloid, are practical; though, generally speaking, a proportion of 2 to 3% gives the optimum result. Where the higher fattyal cohol is appliedas a coating to theemulsiomit shouldbe applied as a thin layer, e. g. 1.0 to 5.0 thick. Such a layer, coated on the surface of an unprocessed emulsion, does not seriously affect the processing of the emulsion with the normal processing liquids.

Two photographic elements of the type described above are illustrated in the accompanying drawing wherein Fig. 1 constitutes a sectional view of one type of element, and

Fig. 2 is a sectional view of another type of element.

Referring now to Fig. 1, a film base I has coated on one side thereof a gelatino-silver halide emulsion layer 2 which has uniformly dispersed therethrough a higher unsubstituted, saturated,

aliphatic, primary monohydric alcohol of at least 12 carbon atoms and which is solid at ordinary temperatures.

The film element of Fig. 2 consists of a film base I which has dispersed on one side thereof a gelatino-silver halide emulsion layer 2 on which there is coated a layer 3 which is composed of gelatin which has uniformly dispersed therethrough an alcohol of the aforementioned type.

Whilst this invention is primarily concerned with the treatment of the photographic emulsion during its manufacture or at some stage prior to processing, a layer containing a higher fatty alcohol may be coated, in accordance with this invention, on the surface of fully processed materials, e. g. on either or both surfaces of processed cine film where the higher fatty alcohol assistsin the prevention of the scratch marks which commonly arise during the running of the film through projector mechanism.

The following example illustrates the invention:

Example Gelatin ms Teepol X cc 40 Water do" 80 stearyl alcohol do 2 Teepol X is a commercial anion-active composition containing about active agent. The dispersion was prepared by melting the above ingredients together and vigorously stirring while allowing the composition to cool to about room temperature. After the addition of the disper sion to the emulsion, the emulsion was coated on glass plates and dried b the usual technique.

It was found that the coated plates were much 7 less easily scratched than corresponding plates prepared without the addition of the stearyl alcohol.

What we claim is:

1. A photographic element comprising a supmer consisting of gelatin which has uniformly dispersed therethrough a small proportion of a surface-active wetting agent and from 0.5 to 10.0% by weight of an unsubstituted, saturated, aliphatic, primary monohydric alcohol of at least 12 carbon atoms and which is solid at ordinary temperatures based on the gelatin.

3. A photographic element comprising a support bearing a light-sensitive gelatino-silver halide emulsion layer and ,having in an outer layer of said element asingle film-forming polymer consisting of gelatin which has uniformly dispersed therethrough from 0.5 to 10.0% by weight of stearyl alcohol based on the gelatin.

4. A photographic element comprising a support bearing a light-sensitive gelatino-silver halide emulsion layer which has uniformly dispersed therethrough from 0.5 to 10.0% by weight of an unsubstituted, saturated, aliphatic, primary monohydric alcohol of at least 12 carbon atoms and which is solid at ordinary temperatures based on the gelatin, said gelatin being the only filmforming polymer in the emulsion layer.

5. A photographic element comprising a support bearing a light-sensitive gelatino-silver halide emulsion layer which has uniformly dispersed therethrough a small proportion of a surface-active wetting agentand from 0.5 to 10.0% by weight of an unsubstituted, saturated, aliphatic, primary monohydric alcohol of at least 12 carbon atoms and which is solid at ordinary temperatures based on the gelatin, said gelatin being the only film-forming polymer in the emulsion layer. I

6. A photographic element comprising a support bearing a light-sensitive gelatino-silver halide emulsion layer which has uniformly dispersed therethrough from 0.5 to 10.0% by weight of stearyl alcohol based on the gelatin, said gelatin being the only film-forming polymer in the emulsion layer.

7. A photographic element comprising a support bearing a light-sensitive gelatino-silver halide emulsion layer having coated thereon an outer layer consisting of gelatin as the sole filmforming polymer which has uniformly dispersed therethrough from 0.5 to 10.0% by weight of an unsubstituted, saturated, aliphatic, primary monohydric alcohol of at least 12 carbon atoms and which is solid at ordinary temperatures based on the gelatin.

WILFRH) HAMPDEN DIMSDALE. KENNETH JOHN CHALLIS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,411,677 Trivelli Apr. 4, 1922 2,118,059 Slack et al May 24, 1938 2,271,622 Carroll et al.' Feb. 3, 1942 2,271,623 Carroll Feb. 3, 1942 2,272,191 Fierke Feb. 10, 1942 2,275,727 Carroll et a1 Mar. 10, 1942 2,304,939 Mannes et al. Dec. 15, 1942 2,304,940 Mannes et al. Dec. 15, 1942 FOREIGN PATENTS Number Country Date 514,251 Great Britain Nov. 3, 1939 Certificate of Correction Patent No. 2,454,043. November 16, 1948.

WILFRID HAMPDEN DIMSDALE ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 3, line 31, under the heading Example, insert the following paragraph:

To 2000 cc. of a gelatin silver iodobromide emulsion was added a dispersion of the following composition: and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 7th day of June, A. D. 1949.

THOMAS F. MURPHY,

Assistant Uommissioner of Patents. 

